The present invention relates to a push switch installed in an operating section of an electronic apparatus.
As a variety of electronic apparatuses have been reduced in the overall size or the thickness, push switches used in those electronic apparatuses are also required to be down-sized.
A conventional push switch comprises a switch case made of insulating resin, protruding contacts arranged integral with a connector terminal accommodated in a recess of the case, and a movable contact. The protruding contacts are fixed by insert-shaping technique to project by a predetermined distance from the bottom of the recess. The movable contact electrically connects and disconnects between the protruding contacts.
A conventional push switch having such a construction will be explained referring the relevant drawings.
FIG. 9 is an upper view of the switch case of the push switch, FIG. 10 is a cross sectional view taken along the line 10xe2x80x9410 of FIG. 9, and FIG. 11 is a cross sectional view taken along the line 11xe2x80x9411 of FIG. 9. A center contact 2 and an outer fixed contact 3 both having a protrusion are fixed by insert-shaping technique on the bottom of an recess of a box-shape switch case 1 made of insulating resin. The contacts 2 and 3 link integrally with connector terminals 2A and 3A, respectively, which extend out of the switch case 1. The linking portions, leads 2B and 3B, are bent to extend substantially in parallel with the bottom of the recess of the switch case I and embedded in the switch case 1. The contacts 2 and 3 are usually bent at their ends 2C and 3C downwardly, while securely embedded in the bottom of the case 1. A movable contact 4 made of elastic thin metal has an upwardly curved dome shape. The movable contact 4 is placed with its outer rim 4A directly on the outer fixed contact 3 in the case 1. The outer rim 4A of the movable contact 4 is electrically insulated from the lead 2b of the center contact 2 by the insulating resin of the switch case 1 covering the upper surface of the lead 2B. The movable contact 4 is protected at the upper side with a flexible insulating film 5 on which an adhesive is applied at the lower side thereof. The film 5 is bonded to a side wall 1A around the recess of the switch case 1 for covering the upper opening of the switch case 1. The film 5 is also bonded to a center top 4B of the movable contact 4 for holding the contact 4 at a certain location in the case 1, thus protecting the inside of the switch case 1 from any dusts such as fluxes.
The operation of the conventional push switch will now be explained. When the insulating film 5 is pressed from above with a pressing force, the movable contact 4 is also pressed through the film. As the pressing force exceeds a certain level, the dome shape of the movable contact 4 is turned over to press with its center top 4b, and the contact 4 makes the center fixed contact 2 electrically connect with the outer fixed contact 3 via the movable contact 4, thus connecting between the two connector terminals 2A and 3A to turn the switch on. Then, when the pressing force is canceled, the movable contact 4 returns back to its original dome shape by a spring back force, and the switch returns back to be turned off shown in FIG. 9.
In the conventional push switch, the leads 2B and 3B of the fixed contacts 2 and 3 are bent at their ends 2C and 3C and embedded in the bottom of the switch case 1. And the bottom of the switch case 1 needs hence to be thick enough for accommodating the leads 2B and 3B therein. Accordingly, the conventional push switch is hardly reduced in the overall thickness.
A push switch is provided which having a bottom thereof reduced in the thickness in spite of embedding fixed contacts in the bottom.
In the push switch, a pair of fixed contacts made of metal strip and embedded in the bottom of the switch case electrically be connected and disconnected to each other by pressing a movable contact. In particular, the fixed contacts have thinner embedded portions than the other portions of them. Accordingly, as the fixed contacts are embedded at their thin portions in the switch case made of insulating resin, the push switch is reduced in the overall thickness without difficulty.